Health and Safety Information 110
The ratings are not guarantees. Results will vary depending on
the user's hearing device and hearing loss. If your hearing device
happens to be vulnerable to interference, you may not be able to
use a rated mobile device successfully. Trying out the mobile
device with your hearing device is the best way to evaluate it for
your personal needs.
M-Ratings
: Mobile devices rated M3 or M4 meet FCC
requirements and are likely to generate less interference to
hearing devices than mobile devices that are not labeled. M4 is
the better/higher of the two ratings.
T-Ratings
: Mobile devices rated T3 or T4 meet FCC requirements
and are likely to generate less interference to hearing devices
than mobile devices that are not labeled. T4 is the better/higher
of the two ratings.
Hearing devices may also be rated. Your hearing device
manufacturer or hearing health professional may help you find
this rating. Higher ratings mean that the hearing device is
relatively immune to interference noise. The hearing aid and
wireless mobile device rating values are then added together.
A sum of 5 is considered acceptable for normal use. A sum of 6
is considered for best use.
In the above example, if a hearing aid meets the M2 level rating
and the wireless mobile device meets the M3 level rating, the
sum of the two values equal M5. This is synonymous for T
ratings. This should provide the hearing aid user with “normal
usage” while using their hearing aid with the particular wireless
mobile device.
“Normal usage” in this context is defined as a signal quality that
is acceptable for normal operation. The M mark is intended to be
synonymous with the U mark. The T mark is intended to be
synonymous with the UT mark. The M and T marks are
recommended by the Alliance for Telecommunications Industries
Solutions (ATIS). The U and UT marks are referenced in Section
20.19 of the FCC Rules.
M3 + M2 = 5
T3 + T2 = 5